This application is based on Patent Application Nos. 139602/1998 filed on May 21, 1998 in Japan, 262804/1998 filed on Sep. 17, 1998 in Japan, 280739/1998 filed on Oct. 2, 1998 in Japan, 304374/1998 filed on Oct. 26, 1998 in Japan, 326931/1998 filed on Nov. 17, 1998 in Japan and 60393/1999 filed on Mar. 8, 1999 in Japan, the content of which is incorporated hereinto by reference.
1. Field of the Invention
The present invention relates to a three-dimensional representation method and an apparatus capable of electronically reproducing a moving picture or video with a reduced amount of information on a three-dimensional image.
2. Description of the Prior Art
A liquid crystal shutter eyeglasses system shown in FIG. 1 is well known as a conventional system which is electrically rewritable, has a small amount of information and can display a three-dimensional video.
The working principle of the liquid crystal shutter eyeglasses system will be explained below.
In this liquid crystal shutter eyeglasses system, a three-dimensional object xcex11 is shot by cameras (xcex12, xcex13) from different directions to generate images (parallactic images) representing the three-dimensional object xcex11 as viewed from different directions.
The images taken by the cameras (xcex12, xcex13) are combined by a video signal converter xcex14 into a single video signal and fed into a two-dimensional display (for example, CRT display) xcex15.
An observer xcex17 views an image on the two-dimensional display xcex15 by wearing liquid crystal shutter eyeglasses xcex16.
Here, when the two-dimensional display xcex15 is displaying an image from the camera xcex13, the liquid crystal shutter eyeglasses xcex16 are made opaque on the left side and transparent on the right side. When the two-dimensional display xcex15 is displaying an image from the camera xcex12, the liquid crystal shutter eyeglasses xcex16 are made transparent on the left side and opaque on the right side.
By switching the above operations at high speed, the viewer feels he is watching parallactic images with both eyes because of the after image affect and therefore can see the object three-dimensionally because of binocular parallax.
Further, a volumetric system as shown in FIGS. 2A and 2B as been proposed as one of the conventional systems that are electrically rewritable, have a small amount of information and can display a three-dimensional video.
The working principle of this volumetric system is explained in the following.
In the volumetric type, as shown in FIG. 2B, a three-dimensional object xcex21 is sampled in the direction of depth as seen from the viewer to generate a set of two-dimensional images xcex22, which is reproduced in a depth direction on a time division basis on a volumetric three-dimensional display xcex23 to display a reproduced three-dimensional image xcex24.
The liquid crystal shutter eyeglasses system shown in FIG. 1, however, has a drawback that because of the required use of the liquid crystal shutter eyeglasses xcex16, the system, when used for teleconferencing, looks very unnatural.
Further, there are large inconsistencies among binocular parallax, convergence and focusing, which are physiological factors of stereoscopy.
That is, in the liquid crystal shutter eyeglasses system shown in FIG. 1, although the requirements of binocular parallax and convergence are almost met, this system will cause eyestrain because the focal plane is on the display surface.
In the volumetric type shown in FIGS. 2A and 2B, the depth positions of the reproduced three-dimensional object xcex21 are close to the surfaces on which images are actually displayed, and are also disposed between these surfaces, so that unlike the liquid crystal shutter eyeglasses system, this volumetric system can suppress contradictions among binocular parallax, convergence and focusing.
With the volumetric system, however, because the depth positions of the reproduced images are discrete, it is difficult to reproduce a three-dimensional object located at an intermediate position between the discreet display positions, or a three-dimensional object that varies greatly in the depth direction.
It is an object of the present invention to provide a three-dimensional representation method and apparatus capable of displaying a video without requiring a viewer to wear glasses.
Another object of the invention is to provide a three-dimensional representation method and apparatus which can suppress contradictions among physiological factors for stereoscopy.
Another object of the invention is to provide a three-dimensional representation method and apparatus which can be electrically erased and programmed.
These and other objects and novel features of the invention will become apparent from the following descriptions in this specification and accompanying drawings.
Representative aspects of the present invention may be briefly summarized as follows.
This invention is characterized by a three-dimensional representation method for generating a three-dimensional image by displaying two-dimensional images on a plurality of image planes located at different depth positions, the method comprising the steps of: generating two-dimensional images by projecting an object to be presented, along the line of sight of an observer, onto a plurality of image planes located at different depth positions as seen from the observer; and changing brightness levels of the generated two-dimensional images individually for each image plane and displaying the generated two-dimensional images on the plurality of image planes.
According to the invention, when the object to be presented is displayed at a depth position close to the observer, the brightness levels of the two-dimensional images displayed on those image planes of the plurality of image planes which are close to the observer may be raised and the brightness levels of the two-dimensional images displayed on the image planes remote from the observer may be lowered. When the object to be presented is displayed at a depth position remote from the observer, the brightness levels of the two-dimensional images displayed on those image planes of the plurality of image planes which are close to the observer may be lowered and the brightness levels of the two-dimensional images displayed on the image planes remote from the observer may be raised.
The two-dimensional images are displayed on the plurality of image planes in such a way that the two-dimensional images overlap each other when the two-dimensional images are viewed from one point on a line which passes through the right and left eyes of an observer, and that an overall brightness level as seen by the observer is equal to the brightness level of the original object to be presented.
According to the invention, the two-dimensional images are arranged to overlap by viewing from one point on the line which passes through the right and left of the observer and the two-dimensional images are enlarged or reduced in the horizontal direction respectively.
According to the invention, the two-dimensional images may be switched successively to generate a three-dimensional moving image.
According to the invention, when the two-dimensional images include a plurality of images of an object moving in a direction of depth and the object is moving toward the observer, the brightness levels of the object images displayed on the plurality of image planes may be progressively raised toward an image plane close to the observer and progressively lowered toward an image plane remote from the observer in synchronism with the successive switching of the two-dimensional images, and when the two-dimensional images include a plurality of images of an object moving in a direction of depth and the object is moving away from the observer, the brightness levels of the object images displayed on the plurality of image planes may be progressively lowered toward an image plane close to the observer and progressively raised toward an image plane remote from the observer in synchronism with the successive switching of the two-dimensional images.
According to the invention, a three-dimensional display may comprise: a first means for generating two-dimensional images by projecting an object to be presented, along the line of sight of an observer, onto a plurality of image planes located at different depth positions as seen from the observer; a second means for displaying the two-dimensional images generated by the first means on the plurality of image planes located at different depth positions as seen from the observer; and a third means for changing brightness levels of the two-dimensional images displayed on the plurality of image planes individually for each image plane.
According to the invention, the second means may comprise: a plurality of two-dimensional displays; and partial reflecting mirrors combined with the plurality of two-dimensional displays except for one two-dimensional display located at the remotest depth position from the observer, the partial reflecting mirrors being adapted to locate images of the two-dimensional displays on the line of sight of the observer.
According to the invention, the second means may comprise: a plurality of two-dimensional displays; and combinations of partial reflecting mirrors and lenses, the partial reflecting mirror and lens combinations being combined with the plurality of two-dimensional displays except for one two-dimensional display located at the remotest depth position from the observer, the partial reflecting mirror and lens combinations being adapted to locate images of the two-dimensional displays on the line of sight of the observer.
According to the invention, the second means may comprise: a plurality of two-dimensional displays; a total reflecting mirror or partial reflecting mirror combined with one of the plurality of two-dimensional displays which is located at the remotest depth position from the observer, the total reflecting mirror or partial reflecting mirror being adapted to locate an image of the one two-dimensional display on the line of sight of the observer; and partial reflecting mirrors combined with the two-dimensional displays except for the one two-dimensional display located at the remotest depth position from the observer, the partial reflecting mirrors being adapted to locate images of the two-dimensional displays on the line of sight of the observers.
According to the invention, the second means may comprise: a plurality of two-dimensional displays; a combination of a total reflecting mirror and a lens or a combination of a partial reflecting mirror and a lens, the combination being combined with one of the plurality of two-dimensional displays which is located at the remotest depth position from the observer, the combination being adapted to locate an image of the one two-dimensional display on the line of sight of the observer; and combinations of partial reflecting mirrors and lenses, the combinations being combined with the two-dimensional displays except for one two-dimensional display located at the remotest depth position from the observer, the combinations being adapted to locate images of the two-dimensional displays on the line of sight of the observer.
According to the invention, the second means may comprise: a plurality of scatter plates capable of controlling a switching between a transmitting state and a scattering state or a plurality of reflection plates capable of controlling the switching between a reflecting state and a transmitting state, the scatter plates or reflection plates being located at different depth positions as viewed from the observer; a plurality of projection type two-dimensional displays for projecting two-dimensional images onto the plurality of scatter plates or the plurality of reflection plates; and a plurality of shutters disposed between the plurality of scatter plates or reflection plates and the plurality of projection type two-dimensional displays, the plurality of shutters being adapted to switch between a transmitting state and a cutoff state in synchronism with the switching between the transmitting state and the scattering state of the plurality of scatter plates or between the reflecting state and the transmitting state of the plurality of reflection plates.
According to the invention, a lens optical system may be disposed between the observer and the plurality of image planes located at different depth positions as seen from the observer.
According to the invention, the second means may comprise a two-dimensional display, an optical system, and a varifocal mirror.
According to the invention, the second means may comprise: a vibration screen which vibrates in the direction of depth; an optical system including a lens; a scanning means for raster-scanning a laser beam; and a laser beam source.
According to the invention, the second means may comprise: an LED display having an LED array; a parallel advancing/rotating device for parallelly advancing/rotating the LED display; and a video feeding device for feeding a video signal to the LED display.
According to the invention, the second means may comprise: a film having a two-dimensional image recorded therein or two-dimensional display; an image transforming optical system having a prism or mirror; and a projection drum.
According to the invention, the second means may successively switch the two-dimensional images generated by the first means to generate a moving three-dimensional image.
According to the invention, when the two-dimensional images generated by the first means include a plurality of images of an object moving in a direction of depth and the object is moving toward the observer, the third means may progressively raise the brightness levels of the object images displayed on the plurality of image planes toward an image plane close to the observer and progressively lower the brightness levels of the object images toward an image plane remote from the observer in synchronism with the successive switching of the two-dimensional images by the second means, and when the object is moving away from the observer, the third means may progressively lower the brightness levels of the object images displayed on the plurality of image planes toward an image plane close to the observer and progressively raise the brightness levels of the object images toward an image plane remote from the observer in synchronism with the successive switching of the two-dimensional images by the second means.
The above and other objects, effects, features and advantages of the present invention will become more apparent from the following description of embodiments thereof taken in conjunction with the accompanying drawings.